Polycarbonates Derived from Glucose via an Organocatalytic Approach

Abstract

An organocatalyzed ring-opening polymerization methodology was developed for the preparation of polycarbonates derived from glucose as a natural product starting material. The cyclic 4,6-carbonate monomer of glucose having the 1, 2, and 3 positions methyl-protected was prepared in three steps from a commercially available glucose derivative, and the structure was confirmed by means of NMR and IR spectroscopies, electrospray ionization mass spectrometry (MS), and single-crystal X-ray analysis. Polymerization of the monomer, initiated by 4-methylbenzyl alcohol in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene as the organocatalyst, proceeded effectively in a controlled fashion to afford the polycarbonate with a tunable degree of polymerization, narrow molecular weight distribution, and well-defined end groups, as confirmed by a combination of NMR spectroscopy, gel-permeation chromatography, and MALDI-TOF MS. A distribution of head-to-head, head-to-tail, and tail-to-tail regiochemistries was determined by NMR spectroscopy and tandem MS analysis by electron transfer dissociation. These polycarbonates are of interest as engineering materials because of their origination from renewable resources combined with their amorphous character and relatively high glass transition temperatures as determined by X-ray diffraction and differential scanning calorimetry studies.

Broad Spectrum Macromolecular Antimicrobials with Biofilm Disruption Capability and In Vivo Efficacy

“…The successful application of aliphatic polycarbonates as macromolecular antimicrobial agents stems from the ease of incorporating many desired functionalities . The incorporation of functionality at either the monomer level or post‐polymerization has enabled the synthesis of well‐defined polycarbonates, including macromolecular antimicrobials. Among the numerous designs of antimicrobial polycarbonates, the “same centered” design approach (i.e., hydrophobic moiety directly conjugated to the cationic center) has recently been shown to provide a unique combination of activity and selectivity .…”

Activated carbonates: enabling the synthesis of differentiated polycarbonate resins via melt transcarbonation

“…In principle, the introduction of any known electron-withdrawing group on the ortho or para position would lead to an activated carbonate. One could consider activated carbonates, including phosgene, di-, or triphosgene 2 or other examples such as o-nitrophenyl carbonates 4 and bis ( pentafluorophenyl) carbonate 5 to polymerize thermally sensitive monomers. Each of these approaches comes with reactivity benefits, but also with complex design and safety measures (and the corresponding equipment considerations) due to the instability and toxicity of these compounds.…”

Complete Depolymerization and Repolymerization of a Sugar Poly(orthoester)

“…The fast depletion of fossil fuels, as well as the detrimental environmental impact of non‐degradable polymers requires the development of completely degradable polymers obtained from renewable resources . Much effort has been invested, especially in the chemical syntheses of polymerizable monomers from naturally occurring building blocks, such as plant oil, and carbohydrates, as shown in Figure .…”

“…The process involved a methylation, a selective protection–deprotection, and a ring‐closing step. The process was of low efficiency, especially in the ring‐closing step . In another example, Du and co‐workers reported the synthesis of a di‐functional glucose monomer (2,3,4‐tri‐ O ‐acetyl‐alpha‐ d ‐glucosyl bromide) .…”